Cam-lock type fittings for valves and connectors are known in the art. These devices generally function by having a pair of cams which rotate upon a fixed axis from opposite sides of a male fitting such that, upon rotation from an unlocked position to a locked position, the distended portion of each cam extends through openings in the sidewall of the male fitting. When the male fitting is abutted over a female fitting, the rotation of the cams to the locked position causes the distended portion of the cams to wedge against grooves in the side wall of the female fitting to reversibly lock together the two fittings.
The walls of cam-lock fittings are required by industry operating and safety standards to be of a minimum thickness. Additionally, the outer surface of the fitting is necessarily circular and the outer diameter measurement is fixed in dimension by industry standards. Prior art cam-lock fittings have a conventional circular interior. To assure that the wall thickness at the grooves is of minimum thickness, the non-groove portion of the wall must be thicker than that of a comparable fitting which is not a cam-lock type. It necessarily follows, therefore, that the interior diameter of prior art cam-lock fittings must be smaller than the interior diameter of a comparable fitting which is not a cam-lock type.
Since prior art cam-lock type fittings have a relatively small diameter, the cross-sectional area is relatively small at this point in the fitting. This sometimes creates a problem because the smaller cross-sectional area results in a lower fluid flow capacity through this part of the fitting. A bottleneck such as this reduces the fluid flow capacity of a valve and/or entire fluid line coupled to a prior art cam-lock fitting.
Another problem associated with existing cam-lock type fitting designs is that the groove indentation forms a small step along the interior surface at the transition from the part of the fitting where the groove is disposed to the part of the fitting having no groove. The step acts as an obstruction because the bottom and/or sides of the fitting are not even with the bottom and/or sides of the adjacent pipe surface. One particular problem with the step is that it tends to prevent complete drainage of the contents of a tank or fluid line when the drain line from the tank or fluid line is disposed along the same horizontal plane as the bottom of the tank or fluid line.
Accordingly, there is a need for cam-lock type fitting that improves on the existing designs by providing a maximum interior diameter within the flow-through passage of the fitting which substantially eliminates steps within the interior surface while maintaining the other cam-lock groove requirements.